As mobile electronic devices, such as cellular telephones, personal digital assistants (PDAs) and pagers, have become more sophisticated, the range of applications that they may offer has become more extensive. Such devices are now often provided with full color, high resolution liquid crystal displays (LCDs) that enable users to view sophisticated graphics, pictures, and video content. Further, new network access protocols, such as the Evolution Data Optimized (EVDO), Wireless Application Protocol (WAP), and i-Mode protocols, allow users to access Internet content through digital cellular networks. Such advances have considerably increased the volume and variety of content available to users of mobile devices: today, such devices can access much of the same content that was once available only through use of a personal computer connected to the Internet via a land line. Because mobile devices are easily transportable, and thus accessible by a user in any situation, users could benefit by having access to such a wealth of content on their mobile devices.
However, while consumers now have the technical ability to access the same types of content on their mobile devices as on their personal computers, they have yet to embrace such mobile applications. One of the main issues inhibiting the mass adoption of mobile applications today is the lack of a user interface that would allow users to easily and intuitively navigate the depth and breadth of content that has become available.
The traditional solution to navigation of complex applications is to create a hierarchical menu structure that is presented to the user. The user is then required to linearly descend several layers of the hierarchy to find the content they are looking for and, once located, the user is taken out of the menu and into the content. Navigating elsewhere within the application requires the user to exit and re-enter the top of the menu hierarchy, and then descend to the correct content. With such an approach, the content is not organized by relevance, and the user loses the frame of reference as the user is taken out of the menu structure to view the selected content.
While this solution may be adequate for personal computer systems, mobile devices present challenges that necessitate a unique approach to user interface design. For example, most mobile devices are provided with only a limited-function keyboard designed to be operated with one hand, and lack the full-sized keyboard and mouse used to navigate the complex menu structures typical of personal computer applications. Moreover, the displays for mobile devices, while as technically sophisticated as those for personal computers, are typically much smaller (usually less than five inches) than personal computer displays (usually greater than fifteen inches). Consequently, the navigation tools provided for mobile devices must be presented on a smaller scale, so that the user more easily loses their frame of reference while navigating between the menu and content.
Thus, the traditional approach to navigation is significantly deficient when applied to mobile devices, and conventional mobile device interfaces are not adapted to navigate the depth and breadth of content that could be provided through such devices. Because of the lack of an easy to use and intuitive interface for accessing broad content, content providers are unable to adequately serve the needs of mobile device users. Accordingly, there is a need for improved graphical user interfaces for enabling the display and navigation of greater amounts of content on electronic devices, without regard to the size of the display screen or the type of user input devices present on the device.